1. Field of Invention
The present invention relates to a liquid crystal display and, more particularly, to a liquid crystal display employing an active matrix mode.
2. Description of the Related Art
In a liquid crystal display employing an active matrix mode, the pixels are regularly arranged in the directions in which the vertical scan lines and the video signal lines extend. Each pixel is provided with a TFT (thin film transistor), a pixel electrode and a sub-capacitor (a storage capacitor). The thin film transistor includes an input electrode connected to the video signal line and an output electrode connected to the pixel electrode. The pixel electrode faces a common electrode with the liquid crystals between them. The sub-capacitor is electrically connected between the output electrode of the thin film transistor and the pixel electrode in a row arrangement to control the tilting state or alignment of the liquid crystals.
Japanese unexamined Patent Publication No. 2003-150080 discloses a layout of sub-capacitors and sub-capacitor lines in a liquid crystal display employing dot inversion driving. A vertical scan line passes through the center of the pixels aligned in the direction of the scan line. The thin film transistors and the sub-capacitors are alternately arranged at both sides of the vertical scan line. One of two sub-capacitor lines is connected to the sub-capacitor arranged at one side of the vertical scan line and the other sub-capacitor line is connected to the sub-capacitor arranged at the other side of the vertical scan line. Sub-capacitor voltages having phases opposite to each other and varying during the off period of the thin film transistor are provided to the two sub-capacitor lines.
In the liquid crystal display described in the above patent, two sub-capacitor lines are disposed corresponding to one vertical scan line. In addition, the vertical scan line and sub-capacitor line are disposed in the pixel and overlap each other so that the effective aperture ratio of the pixel is reduced and the transmittance of the liquid crystal display is lowered.